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Fabrication of Gate-tunable Graphene Devices for Scanning Tunneling Microscopy Studies with Coulomb Impurities
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Electrically Induced Dirac Fermions in Graphene Nanoribbons
Michele Pizzochero1, Nikita V Tepliakov2,3,4, Arash A Mostofi2,3
1School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, United States.
Nano Letters
|October 29, 2021
Summary
Applying electric fields to graphene nanoribbons transforms them into semimetals, creating zero-energy Dirac fermions along edges. This controllable electronic structure transition is key for future carbon-based devices.
Area of Science:
- Condensed Matter Physics
- Materials Science
- Nanotechnology
Background:
- Graphene nanoribbons (GNRs) are promising for next-generation electronics.
- Controlling their electronic structure is crucial for device applications.
Purpose of the Study:
- Investigate the effect of transverse electric fields on armchair GNRs.
- Determine if GNR electronic structures can be externally controlled.
Main Methods:
- Combined simple model Hamiltonians with first-principles calculations.
- Simulated transverse electric fields via lateral gating or codoping.
Main Results:
- Discovered an electric-field-induced semiconductor-to-semimetal transition.
- The semimetallic phase exhibits zero-energy Dirac fermions along armchair edges.
- Transition critical fields inversely scale with nanoribbon width.
Conclusions:
- Electric fields can engineer Dirac semimetallic phases in GNRs.
- Findings are applicable to other group-IV honeycomb nanoribbons (silicene, germanene).
- Offers new pathways for tunable electronic properties in nanostructures.
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